The present invention relates to a method and means for setting up a fabric on a flat knitting machine.
Flat knitting machines have an advantage that they permit widening and narrowing operation, so that fabrics can be fashioned as desired.
However, when fashioning is carried out on a batch basis, the knitting operation involves the following problem at set-up stage. If the final-course width of a fashioned fabric is smaller than that of the set-up course of a next fabric to be fashioned, for example, it is necessary that a large number of waste courses should be provided between the final course of the knitted fabric and the set-up course of the next batch fabric in such a way that the waste courses are sequentially widened until the set-up course width of the next batch fabric is reached. Otherwise, the set-up course of the next batch fabric will be subject to partial stretch and no widthwise uniformity can be obtained in knit construction.
Therefore, in order to reduce the number of waste courses so that no such problem as pointed out above will be encountered even if such fashioning is carried out on a batch basis, there have been proposed a number of set-up methods and a number of set-up devices for carrying out those methods.
For example, Japanese Patent Publication No. 51-2979, as well as Japanese Patent Application Laid-Open Publication No. 59-21762, discloses a (see present FIGS. 21-23) such that a hook-type comb 103 comprising a plurality of set-up needles (crochet needles) 101 each having a hook 102 at its front end, as shown in FIG. 21, is employed in such a way that set-up needles caused to project their front ends upwardly through the 3 between the front and rear needle beds 2f, 2r. In this knitting needles R on one of the needle beds (for example, on the rear needle bed) are brought to their advanced and then a set-up yarn 105 for a first knitting course is supplied between the array of the setting-up needles 101 and the array of the knitting needles R. Thereafter, the knitting needles R are retreated and simultaneously the front ends of the setting-up needles 101 are lowered to a level the gap 3 so that the set-up yarn 105 is laid in zigzag between the set-up needles 101 and the knitting needles R, the set-up comb 103 then being gradually lowered the set-up yarn 105 remains engaged by hooks 102 of the needles 101, whereby a next and subsequent courses can knitted.
Japanese Patent Application Laid-Open Publication No. 45-24306 (U.S. Pat. No. 3,376,716) disclosed another technique. There, a double-comb type set comb consisting of a combination of a comb-shaped array of needles and a comb-shaped array of pin-like needles (not , is employed in such a way that the double-comb type set-up comb is caused to project upward through the gap between the front and rear needle beds while being held in closed position and knitting needles on one of the needle beds are brought to their advanced position passing through the clearance between the eye needle and pin-like needle arrays of the double comb. Thereafter, a set-up yarn for a first knitting course is supplied between the double comb array and the knitting needle array in the same way as in the case of the first mentioned prior-art technque. Then the knitting needles are moved to their retreated position, whereby a set-up yarn course in zigzag pattern is laid between the knitting needles and the set-up comb. The set-up comb is then lowered to a level below the gap between the needle beds so that sinker loops of the set-up course are hooked by the upper ends of eye needles of the set-up comb in closed condition. Subsequently, the set-up comb is gradually lowered to enable knitting of a next and subsequent courses.
In these methods using such known devices, knitting needles only on one of the needle beds are brought to their advanced position and set-up needles are caused to project upward through the gap. As seen in FIGS. 21-23, sinker loops S of the set-up yarn 105 supplied between the set-up needles projecting through the gap and the knitting needles on the one needle bed are hooked by the front end of the set-up comb. As the set-up comb is gradually lowered, a next and subsequent courses are knit. As such, these prior-art techniques involve the following problems.
a) Usually, set-up yarn 105 is supplied between the knitting needles and the set-up comb while being gripped by a suitable gripper 106 as shown in FIG. 22. The starting feed end 105a for the set-up yarn 105 is released from the gripper 106 when the next several and ten-odd courses have been knitted. Therefore, set-up course loops (sinker loops) S.sub.1, S.sub.2, etc., adjacent the starting feed end of set-up yarn 105 are likely to be stretched by the set-up comb 103 as knitting progresses (FIG. 23).
b) Therefore, walewise loops formed in succession to the needle loops N.sub.1, N.sub.2 etc. at the starting end side of the set-up yarn 105 are likely to have no sufficient take-down tension applied thereto and, accordingly, a newly set-up fabric 150 is likely to have no uniform tension given throughout its width. This may often result in distortion (bowing) with the fabric 150 (FIG. 23).
c) If sinker loops S.sub.1, S.sub.2 etc., which are under tension by the set-up comb 103 are stretched, an upper portion 150a adjacent the selvage of the fabric 150 (FIG. 23) has no sufficient tension applied and, therefore, may be often liable to loop dropping in the course of knitting.
The following problems have also been found with the above mentioned prior-art set-up method and device in which a set-up yarn must be supplied to the set-up comb in such condition that the front end of the set-up comb projects substantially above the gap between the front and rear needle beds.
d) The required space above the gap for feeder passage is partially blocked by the front end of the set-up comb and, therefore, at a level above the gap it is necessary to shift the yarn feeder for set-up yarn to keep it away from the set-up comb. As such, yarn feeders available for set-up yarn feed are limited in number and position, because they are required to shift at a level above the gap in order to avoid the possibility of interference with the set-up comb. If the yarn feeder for set-up yarn happens to contact the set-up comb projecting above the gap, there may be the trouble of set-up needle breakage or bending.
e) When the set-up comb is thrusted to a level above the gap, if any yarn feeder is present on the way, the top end of the set-up comb is subject to damage by the yarn feeder. Therefore, when thrusting the set-up comb upward beyond the gap, it is necessary that all the yarn feeders must be kept away from the set-up comb range. This means that each yarn feeder must be previously moved considerably sideward to a position at which the yarn feeder will not collide with the set-up comb.
f) The conventional set-up comb having hook-type setting-up needles such that set-up needles must be thrusted substantially upward beyond the gap between the needle beds for set-up yarn supply. Naturally, therefore, the set-up needles are considerably long. If a long fabric is lowered by the set-up comb, the fabric engaged by setting-up needles is subject to a considerable force acting in a direction of fabric narrowing. Therefore, the trouble with the prior-art set-up comb having long set-up needles is that the needles are subject to deformation. If a setting-up needle is deformed, it is often difficult to disengage the set-up comb from the loop by mechanical means.
g) The conventional set-up comb having hook-type setting-up needles has a disadvantage that it cannot disengage by itself the set-up course loops which are in engagement with its top end and, therefore, it requires some means for disengaging the loops from its top end. However, such means cannot be provided immediately below the needle beds. In order to disengage the hooks of the set-up comb from the fabric there must be some means for holding the fabric at a level above the hooks of the set-up comb (e.g., means for gripping and taking down the fabric). Therefore, with the prior-art arrangement, it is impossible to disengage the set-up comb from the lower end of the fabric, in case the fabric knitted is somewhat short in length.
h) In this respect, the above mentioned double-comb type set-up comb has an advantage that it is possible to release sinker loops of the set-up course engaged by the top end of the set-up comb by lowering pin-type needles and removing the same through eyelets of eye needles, it being thus possible to disengage the set-up comb from the lower edge of the fabric, even if the fabric knitted is somewhat short in length. However, the difficulty with this latter mentioned set-up device is that accurate control is required for insertion and removal of the front end of each pin-like needle having a certain length relative to the eyelet formed at the curved front end of a corresponding eye needle having a larger length. This, thus, requires a high degree of precision with respect to the arrangement of two comb arrays subject to relative displacement.